Extension scaffold

ABSTRACT

A portable scaffold which is extendable in height as well as length, the device being comprised of a pair of base ladder units held in upright vertical position by means of criss-crossing braces and a horizontal platform across the upper ends, and each of the base ladder units being adaptable for supporting thereon an extension at an adjustable elevation, and the horizontal platform in one form of the invention being telescopic in length.

United States Patent Cullison [54] EXTENSION SCAFFOLD [72] inventor:Eugene Francis Cullison, 5709 Yeary St., Fort Worth, Tex. 761 14 [22]Filed: March 15, 1971 211 App]. No.: 124,285

521 U.S.Cl. ..l82/ll9,182/l78,182/209,

182/223 511 lnt.Cl ..E04 1/14 5s FieldofSearch ..l82/ll9,ll8,l78,209,2l0

[56] References Cited UNITED STATES PATENTS 4/1962 Juculano ..l82/17811/1952 Johnson ..l82/l 19 [451 Sept. 12, 1972 Hawkes 1 82/209 Kosmach..l82/l78 Primary Examiner-Reinaldo P. Machado [5 7] ABSTRACT A portablescaffold which is extendable in height as well as length, the devicebeing comprised of a pair of base ladder units held in upright verticalposition by means of criss-crossing braces and a horizontal platformacross the upper ends, and each of the base ladder units being adaptablefor supporting thereon an extension at an adjustable elevation, and thehorizontal platform in one form of the invention being telescopic inlength.

1 Claim, 6 Drawing Figures PATENTEDsEP 12 m2 3 590.407

saw 1 [IF 2 PATENTEDSEP 12 m2 SHEET 2 [IF 2 EXTENSION SCAFFOLD Thisinvention relates generally to extension scaffolds.

A principal object of the present invention is to provide an improvedextension scaffold, particularly designed for a workingman to reacheither a high or low cealing, and which is accordingly adjustable inheight.

Another object of the present invention is to provide an extensionscaffold which is accordingly suitable for either a short or tall man.

Still another object is to provide an extension scaffold which isadjustable in horizontal length so as to be readily able to be fittedwithin a room.

Other objects of the present invention are to provide an extensionscaffold which is simple in design, inex pensive to manufacture, ruggedin construction, easy to use and efficient in operation.

These and other objects will be readily evident upon a study of thefollowing specification and the accompanying drawings wherein:

FIG. 1 is a perspective view of the present invention,

FIG. 2 is a fragmentary cross-sectional view taken on the line 2-2 ofFIG. 1,

FIG. 3 is a cross-sectional view taken on the line 3- 3 of FIG. 2,

FIG. 4 is a top plan view of a modified design of horizontal platformwhich is longitudinally telescopic,

FIG. 5 is a fragmentary perspectiave view of one of the sliding membersof the telescopic platform illustrated in FIG. 4, and

FIG. 6 is a perspective view of a modified design of brace which isadjustable in length.

Referring now to the drawings in detail, and more particularly at thistime to FIGS. 1 to 3 thereof, the reference numeral 10 represents anextension scaffold according to the present invention wherein there area pair of spaced apart base ladder units 11 each one of which iscomprised of a pair of parallel, spaced apart runners 12 between whichthere are a series of transverse extending rungs 13.

At the lower ends of the runners 12 there are a pair of rollers orwheels 14 so to permit the base ladder unit to travel across the surfaceof a floor 15, or if used out of doors then being supported upon aground.

Each one of the runners 12 has a semi-cylindrical guard rail 16 securedto one side thereof so that an extension 17 can be slideably fittedthere into as is indicated by the arrows 18.

The base ladder units 11 are supported in an upright position by meansof a pair of criss-crossing braces 19 each one of which at theiropposite ends is provided with a hook 20 for being fitted around one ofthe rungs 13 as is shown in FIG. 1 of the drawing.

A horizontal platform 21 can be supported between the base units 11 asshown in FIG. 1, the platform 21 including a rigid panel 22 which at itsopposite ends is provided with a pair of extending hooks 23 made ofstiff metal bar material, the hooks 23 being adaptable for being hookedabout a rung 13 on each one of the base units 11.

Each one of the extensions 17 comprises a ladder member consisting of apair of parallel, spaced apart runners 24 which are interconnected bymeans of transverse extending rungs 25 located there between.

The runners are spaced apart a precise distance so that the runners arereadily receivable into the guide rails 16.

Near the lower end of each of the runners 24, there is secured a pivotlyfree hook 26 attached thereto by means of a rivet or bolt 27.

As shown particularly in FIGS. 2 and 3 of the drawing, the extensionsare secured at a desired elevation upon the base units by means of thehooks 26 being grasped around a selected one of the rungs 13 of the baseunit 11.

It will now be evident that in operative use, the extension scaffold canbe directed to accommodate any height of man and accommodating anyheight of a room ceiling.

Referring now to FIGS. 4 through 6, there is shown a modified design ofthe invention wherein the above described platform 21 is substituted bya telescopic platform 28 and by longitudinally adjustable braces 29 sothat the extension scaffold can be erected in any horizontal length soas to suit the size of a room.

The telescopic platform 28 is comprised of intersliding platform units30 and 31 each one of which is comprised of a series of parallel, spacedapart beams 32 with spaces 33 there between. The beams 32 in each one ofthe units are rigidly secured to a transverse member 34, the oppositeends of the beams 32 being secured between an upper and lower metalplate 35 by means of bolts 36.

As shown in FIG. 5 of the drawing, it is now evident that the spaces 33between the beams 32 are adaptable to receive the beams of the otherinterslideable unit so that the units are readily telescopic in alongitudinal position, as is indicated by the arrows 37.

Thus there is provided a telescopic platform. In order to accommodatethe scaffold length, the above described braces 19 are in this form ofthe invention substituted by the adjustable braces 29, each one of whichis comprised of a pair of brace bars 38 and 39, one of which has aseries of openings 40 therethrough and the other of which has a seriesof longitudinally extending slots 41, the openings 40 and slots 41 beingadaptable for receiving interconnecting bolts 42 secured by nuts 43.Thus the braces are adjusted in size so as to accommodate the length ofthe platform 28 so to form a scaffold of any desired length.

The telescopic brace 29 is, of course, provided with a hook 44 at eachopposite end thereof for being received around the rungs 13 of the baseunit.

What I now claim is:

1. In an extension scaffold, the combination of a pair of spaced apartladder base units, each one of said base units being comprised of a pairof parallel, spaced apart runners which are inter-connected bytransverse extending rungs, a pair of criss-crossing braces beingprovided for erecting said base units in an upright position, each oneof said braces having a hook at its opposite ends for being hookedaround said rungs, and a horizontal extending platform being supportedbetween said base units, said platform at its opposite ends beingprovided with strong metal hooks for fitting around said rungs, saidscaffold including a pair of extensions, each one of said extensionsbeing adaptable for being adjustably secured to said base units, each ofsaid base units having a semi-cylindrical guard rail said runners ofsaid extension being adaptable for being hooked selectively around oneof said rungs of said base unit, and said platform being telescopic bycomprising a pair of interslidable units.

1. In an extension scaffold, the combination of a pair of spaced apartladder base units, each one of said base units being comprised of a pairof parallel, spaced apart runners which are inter-connected bytransverse extending rungs, a pair of crisscrossing braces beingprovided for erecting said base units in an upright position, each oneof said braces having a hook at its opposite ends for being hookedaround said rungs, and a horizontal extending platform being supportedbetween said base units, said platform at its opposite ends beingprovided with strong metal hooks for fitting around said rungs, saidscaffold including a pair of extensions, each one of said extensionsbeing adaptable for being adjustably secured to said base units, each ofsaid base units having a semi-cylindrical guard rail secured to each oneof said runners, each said extension comprising a ladder memberincluding extensions receivable into said guard rails, said runnersbeing inter-connected by transverse extending rungs, a pivotable hooksecured to a lower end of each one of said runners of said extensionbeing adaptable for being hooked selectively around one of said rungs ofsaid base unit, and said platform being telescopic by comprising a pairof interslidable units.